From: Eric Dumazet <dada1@cosmosbay•com>
To: Jarek Poplawski <jarkao2@gmail•com>
Cc: David Miller <davem@davemloft•net>, netdev@vger•kernel.org
Subject: Re: [RFC] net: release dst entry in dev_queue_xmit()
Date: Wed, 25 Mar 2009 20:40:05 +0100 [thread overview]
Message-ID: <49CA8895.8020105@cosmosbay.com> (raw)
In-Reply-To: <20090325191850.GA2928@ami.dom.local>
Jarek Poplawski a écrit :
> On Wed, Mar 25, 2009 at 07:41:27PM +0100, Eric Dumazet wrote:
>> Jarek Poplawski a écrit :
>>> David Miller wrote, On 03/25/2009 08:17 AM:
>>>
>>>> From: Eric Dumazet <dada1@cosmosbay•com>
>>>> Date: Wed, 25 Mar 2009 08:13:30 +0100
>>>>
>>>>> If done in dev_hard_start_xmit(), skb could be requeued (because of
>>>>> NETDEV_TX_BUSY). Then if requeued, maybe at this time, dst being
>>>>> NULL is not a problem ?
>>>> Usually it should be OK because the packet schedulers have
>>>> a sort-of one-behind state that allows them to reinsert
>>>> the SKB into their queue datastructures without reclassifying.
>>>
>>> Actually, since David has dumped requeuing there is no reinserting;
>>> this last one "requeued" skb is buffered at the top in q->gso_skb
>>> and waiting for better times.
>> Yes indeed, this is what I thought too, thanks Jarek.
>
> Alas I'm a bit concerned with virtual devs, e.g. now I'm looking at
> xmits in macvlan and pppoe. Maybe this patch should exclude them?
>
Yes, MACVLAN :) its macvlan_start_xmit() function calls
dev_queue_xmit(skb) again, so we go back to packet schedulers and
classifiers, they might need dst again :(
Only other potential problem I found was in
drivers/net/appletalk/ipddp.c
static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
{
__be32 paddr = ((struct rtable*)skb->dst)->rt_gateway;
Not sure this driver is still supported, or if this paddr can be found elsewhere...
__sk_dst_get(skb->sk) ???
next prev parent reply other threads:[~2009-03-25 19:40 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-20 11:40 [RFC] net: release dst entry in dev_queue_xmit() Eric Dumazet
2009-03-20 14:10 ` Neil Horman
2009-03-25 6:43 ` David Miller
2009-03-25 7:13 ` Eric Dumazet
2009-03-25 7:17 ` David Miller
2009-03-25 18:22 ` Jarek Poplawski
2009-03-25 18:41 ` Eric Dumazet
2009-03-25 19:18 ` Jarek Poplawski
2009-03-25 19:40 ` Eric Dumazet [this message]
2009-03-25 19:54 ` Jarek Poplawski
2009-03-25 20:28 ` Eric Dumazet
2009-03-25 21:12 ` Jarek Poplawski
2009-03-25 21:20 ` Patrick McHardy
2009-05-12 8:12 ` [PATCH] net: release dst entry in dev_hard_start_xmit() Eric Dumazet
2009-05-12 8:21 ` Eric Dumazet
2009-05-12 19:26 ` [PATCH, v2] " Eric Dumazet
2009-05-19 5:19 ` David Miller
2009-05-19 5:44 ` Eric Dumazet
2009-05-19 19:44 ` Eric Dumazet
2009-05-19 21:09 ` Jarek Poplawski
2009-05-19 21:21 ` Eric Dumazet
2009-05-19 21:24 ` David Miller
2009-05-12 19:27 ` [PATCH] " Jarek Poplawski
2009-05-12 19:44 ` Eric Dumazet
2009-05-12 20:05 ` Jarek Poplawski
2009-05-12 20:24 ` Jarek Poplawski
2009-05-12 20:52 ` Eric Dumazet
2009-05-12 20:59 ` Jarek Poplawski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=49CA8895.8020105@cosmosbay.com \
--to=dada1@cosmosbay$(echo .)com \
--cc=davem@davemloft$(echo .)net \
--cc=jarkao2@gmail$(echo .)com \
--cc=netdev@vger$(echo .)kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox